Railway traffic controlling system



n- 8, 1952 R. F. WELLS 2,582,089

RAILWAY TRAFFIC CONTROLLING SYSTEM Filed June 2, 1945 Patented Jan. 8, 1952 RAILWAY TRAFFIC CONTROLLING SYSTEM Robert. F. Wells, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application June 2, 1945, Serial No. 597,216

This invention relates to electrical control circuit organizations for railway switch and signal ling systems, and more particularly to a circuit organization for governing circuits dependent upon the position and locked condition of the switch points of track switches in interlocking and centralized traffic control systems on railroads.

In. connection with controlling the indications of signals governing train movement over track switches, it is common practice to use a conventional neutral-polar indication relay arranged to be energized by a polarized circuit controlled in accordance with the position and locked condition of switch points, and utilize the position of the polar armature of such indication relay, either with or without repeater relays, to select the signal control circuit in conformity with the position of the switch points. The polar armature of a conventional neutral-polar relay is magnetically held in the last operated position until shifted by a change in the polarity of energization" of the relay; and in a circuit organization using such a neutral-polarrelay for detecting switch point position, if the polar armature of this relay'should fail for some reason to respond to ,a reversal in polarity, it may happen that a signal will be cleared for train movement over the switch points when set in the wrong position for such movement, with the result that a derailment or damage to the switch or its operating mechanism may occur.

Various expedients have been proposed to check the proper response of the polar armature of a neutral-polar switch position indication relay, such as disclosed for example in the patent to Field, No. 2,083,902, June 15, 1937; but since normal and reverse repeater or correspondence relays governed by the polar contact of the indi cation relay are often required and used to provide sufiicient contacts for the circuits involved, the desired protection against faulty operation of the polar contact of the indication relay may be obtained by preventing the improper energization of such repeater relays, and without attempting to check the operation of the polar armature circuits.

The primary object or purpose of the present invention is to provide a simple and eifective circuit organization for governing the normal and reverse correspondence relays controlled by the neutral-polar switch position indication relay,

in such'a manner that failure of the polar armature of the indication relay to respond to a re- 7 Claims. (Cl. 246-219) versal in polarity cannot cause improper energization of the wrong repeater relay. v

Generally-speaking, and without attemping to define-the natureand scope of the present invention, it is proposed to provide for the energization of the normal and reverse repeater relays from the same control circuit governing the switch positionindication relay, and to employ conventional rectifiers in such a way as to block the flow of current through a repeater relay when the control circuit is not energized with the corresponding. proper polarity, and thus prevent its energization if the polar armature of the indication relay should fail to respond to a reversal of polarity in the control circuit, the arrangement of circuits also being such that a repeater relay may not be improperly energized in theevent of a break-down or open circuit condition of a rectisimplifying the illustration, certain conventional showings are used in connection with the illustration of the relays and circuits." The connections to the opposite terminalsof a battery or other suitable source of current are indicatedby arrows and the symbols (4-) and The relay contact fingers are shown as'bein'g in the horizontal position when the relay is energized, and in an inclined position when the relay isdeenergized, these contact fingers being illustrated either above or below the representation of the relay coil or winding and connected thereto by dash lines as is most convenient for illustration of the circuit connections.

In the accompanying drawings, Fig. 1 shows an organization of circuits constituting the invention applied to a typical single switch layout; and Figs,- 2A, 2B and 2C are fragmentary diagrams for explanatory purposes of the energized circuits like for governing circuits in accordance with the polarity of energization of a control circuit, the typical embodiment of the invention illustrated relates to the control of a switch position indieating relay and associated normal and reverse correspondence relay NCR and RCR, in connection with a conventional arrangement of a single power operated switch and associated signals. The switch points of the switch SW are assumed to be connected to and operated by a power operated switch machine SM in the usual way, this switch machine being of any suitable type, such as disclosed for example in the prior patent to Howe, No. 1,466,903, September 4, 1923. The power operation of the switch machine is governed by suitable control circuits indicated diagrammatically in response to the energization of normal and reverse switch control relays WN and WR and closure of their contacts 4 and 5. These switch control relays WN and WR, may be controlled by a suitable switch control means, illustrated schematically in a dotted rectangle, in accordance with the usual practice in interlocking and centralized traffic control systems.

Associated with the switch points, and usually forming part of the switch machine SM, is a circuit controlling device PD, commonly termed a point detector, which'is operated in accordance with the position and the locked condition of the switch points, such as disclosed for example in the patent to Bushnell, No. 1,517,236, November 25, 192%. The point detector structure usually employed involves a number of contacts performing both a shunting and a pole-changing function; but since these details form no part of the present invention, a simple pole-changing switch with contact elements 6 and 1 movable between two extreme positions has been illustrated for this purpose.

The switch position indication relay WP used in the circuit organization of this invention is of the conventonal neutral-polar type, such as disclosed for example in the prior patent to Field, No. 1,749,331, March 4, 1930. This relay WP comprises the usual neutral-armature biased by gravity or a spring to a retracted position, and a two-position polar armature shifted from one extreme position to the other in response to the polarity of energization of the relay, and held in the last operated position magnetically until changed. A neutral contact 8 operated by the neutral armature, and a polar contact 9 operated by the polar armature of the relay WP are illustrated conventionally in the drawings.

In the various forms of interlocking and centralized traffic control systems, it is usually necessary to provide for governing the continuity ot a number of di'fierent circuits dependent upon switch position, andalso in many cases dependent upon correspondence between the switch position and the switch control means; and for this purpose normal and reverse repeater or correspondence relays, such as NCR and RCR are commonly used. In the simplified arrangement illustrated, the control circuits for the signals IRA and ILA governing train movement over the switch SW in its normal position are governed by control circuits shown schematically by dash lines dependent upon the energization of the normal correspondence relay NOR and closure of a front contact such as H]. Similarly, the signals IRB and ILB governing train movement over the switch SW in its reverse position are governed by a front contact ll of the reverse correspondence relay RCR.

The specific electrical connections between the various relays is preferably considered in describing the operation.

Operation-The various reays and circuits are illustrated in the condition corresponding with the switch points over and locked in the normal position. Under these conditions, the indication relay WP is energized with the normal polarity from the control circuit over a conducting path which may be traced from contact element 6 of point detector PD in position shown, wire I4, coil or winding of relay WP, wire l5, through the other contact element 1 of the point detector PD, to

Under the conditions shown for the normal position of the switch, the normal correspond ence relay NCR is also energized from the same control circuit for the relay WP over a conducting path which may be traced from contact element 6 of point detector PD in the position shown, wires M and I6, winding of relay NCR, a front contact ll of normal control relay WN, polar contact 9 of relay WP to the right as shown, neutral contact 8 of relay WP in the attracted position as shown, through a rectifier !9, to wire 55, and thence through the other element 1 of the point detector PD, to These conditions are shown in the fragmentary circuit diagram of Fig. 2A.

The rectifier id just mentioned, and a similar rectifier l8 employed in the energizing circuit for the reverse correspondence relay RCR, may be any suitable form of asymmetric unit, but are preferably of the selenium or copper-oxide dry plate type.

It will be noted that under the conditions illustrated for the normal position of the switch, the normal correspondence relay NCR is energized in multiple with the indication relay WP from the same polarized control circuit including wires M and I5, and that the conducting path for flow of energizing current through the normal correspondence relay NCR includes in series the neutral contact 8 and polar contact 9 of the relay WP, the rectifier I9, and also a front contact I l of the normal switch control relay WN. If the relay NCR. is merely a repeater of the indication relay WP, rather than a correspondence relay, the contact I! of relay WN would not be used.

Assume now that suitable control is exercised to energize the reverse switch control relay WR and deenergize the normal relay WN to operate the switch points to the reverse position. As soon as the switch points are unlocked, the point detector contacts 6 and l are opened to deenergize the indication relay WP and normal correspondence relay NCR in the usual way. After the switch points have been moved and locked in the reverse position, the contact elements 6 and l of the point detector PD assume the lower dotted line position to energize the control circuit including wires .[4 and IS with the other reverse polarity.

Assuming normal operating conditions, this reversal of polarity of the control circuit causes the polar armature 9 of the relay WP to shift to the left-hand dotted line position, and restore the neutral armature to its attracted position, whereupon a circuit for energizing the reverse correspondence relay RCR is established which may be traced from through contact element 6 in its lower position, wires I 5 and 20, relay RCR, front contact 2| of relay WR, polar contact 9 of relay WP to the left, neutral contact 8 of relay WP, rectifier l8 and wire I l through the other contact element 1 of the point detector PD in its dotted line position to These conditions are illustrated in the fragmentary circuit diagram of Fig. 2B.

Considering now the protection afiorded. in accordance with this invention against improper energization of a, correspondence relay, in the event that the polar armature 9 of the indication relay WP should for some reason fail to respond to a reversal of polarity, assume'that such failure occurs with this polar contact 9 in the normal position. When the polarity is reversed and (-1-) is connected to the lower wire l5 of the control circuit, it can be seen that the flow of current through the normal correspondence relay NCR, is blocked by the rectifier I9, so that regardless of the failure of the polar armature 9 of the relay WP to assume the reverse position in accordance with the polarity of energization of thecontrol circuit, and independently of the front contact I! of the normal switch control relay WN, the'normal correspondence relay NCR cannot be energized under these conditions, which are indicated in the fragmentary circuit diagram of Fig. 20.

Thus, if the switch points should be operated to the reverse position, for example, and the polar contact 9 of the relay WP should fail to shift properly to the corresponding left-hand dotted line position, and the relay WN should for some reason he energized, the normal correspondence relay NCR cannot be energized to give a control of the signals as if the switch points were in the normal position, when they are in fact in the reverse position.

The other rectifier l8 performs a similar protective function in preventing improper energization of the reverse correspondence relay RCR.

Considering the check upon the integrity of the rectifiers l8 and I9 and their connecting circuits, and assuming the control circuit to be energized with the polarity shown, if the rectifier 18 in the circuit for the relay NOR should break down and become conductive both ways, then the winding of the indication relay WP is shortcircuited or shunted through the two rectifiers I9 and I8 in series, so that it is deenergized and opens its front contact 8 to prevent energization of either relay NCR or RCR. The same is true if the other rectifier 19 should break down with the control circuit energized with the reverse polarity.

If, under the conditions shown in Fig. 1 and Fig. 2A, the rectifier l9 in the energizing circuit for relay NOR or the circuit connections thereto, should for some reason develop an open-circuit condition, the relay NCR is deenergized; and if such open-circuit condition should exist in connection with the other rectifier 18, the other relay RCR cannot be energized.

From the foregoing, it can be seen that this invention provides a simple and efiective circuit organization for protecting against false operation due to failure of the polar contact of a neutral-polar relay to shift in response to a reversal in polarity of the energization of its control circuit, and that the rectifiers employed to provide this protective function are fully checked against break-down or open-circuit conditions.

The particular embodiment of the invention shown and described is merely typical of one particular organization and application of the functions and mode of operation characterizing the invention; and it is desired to have it understood that various adaptations, modifications, and additions may be made in the particular arrangement of circuits and relays shown and described without departing from the invention.

What I claim is:

1. In an electrical control organization for railway signalling systems, the combination with a control circuit energized with direct current of different polarity at different times, a neutralpolar indication relay included in said control circuit and having a biased neutral armature and a polar armature for respectively operating neutral and polar contacts, normal and reverse repeater relays, two rectifier units, energizing circuits governed by said neutral and polar contacts for energizing one or the other of said repeater relays in multiple with said indication relay from said control circuit, the energizing circuit for each of said repeater relays including one of said rectifier units acting to block the flow of current through that relay when said control circuit is energized with a polarity opposite to that to which that repeater relay is intended to respond, whereby energization of the wrong repeater relay is prevented upon change in polarity of the control circuit if the polar armature of said indication relay fails to respond to such change in polarity.

2. A control circuit organization for governing circuits in accordance with the polarity of energization of a control circuit comprising, a neutral-polar indication relay included in said control circuit and having neutral and polar contacts, a circuit connection including oppositely poled rectifiers connected in multiple with the winding of said indication relay, normal and reverse neutral repeater relays, and energizing circuits for said repeater relays including the neutral contact and different polar contacts of said indication relay and connected across different rectifiers in said circuit connection, whereby the fiow of current through a repeater relay energized for a given position of the polar armature of said indication relay for a given polarity of energization of said control circuit is blocked upon a reversal in the polarity of energization of said control circuit, and energization of the wrong repeater relay is prevented if the polar armature of the indication relay should fail to respond to such reversal in polarity of the control circuit.

3. In a control circuit organization for railway signalling systems, the combination with a control circuit energized with the uni-directional current of different polarity at different times, a neutral-polar indication relay having a winding included in said control circuit, a circuit connection including oppositely poled rectifiers connected across the winding of said indication relay, two neutral repeater relays one for each polarity of energization of said control circuit, and an energizing circuit for each of said two repeater relays, both such circuits at one end terminating at the mid-point in said circuit connection between said rectifiers and their other ends being respectively connected to said control circuit on opposite sides of said winding through neutral and polar contacts of said indication relay.

4. In a control circuit organization of the character described, the combination with a polarized control circuit, of a neutral-polar indication relay included in said control circuit and having a biased neutral armature and a polar armature operable to different positions, normal and reverse neutral repeater relays each having an energizing circuit closed only if the neutral armature of said indication relay is in its attracted position and its polar armature is in a predetermined corresponding position, said energizing circuits being connected to said control circuit with rectifiers to energize one or the other of said repeater relays in multiple with said indication relay when said control circuit is energized with a corresponding polarity, said rectifier included in each of said energizing circuits acting to block the flow of current through the corresponding repeater relay when said control circuit is energized with a polarity different from the polarity normally causing energization of that repeater relay.

5. In an indication and control circuit organization for a railroad track switch, control means associated with the track switch for governing its operation to normal and reverse positions as required, point detector contacts associated with the track switch and operated to normal and reverse positions in correspondence with the track switch when it is in such positions and locked but said contacts being operated to a distinctive position when the track switch is unlocked or is in operation, a polarized indication circuit governed by said point detector contacts so as to be energized with one polarity when the track switch is in one position and locked and so as to be energized with the opposite polarity when the track switch is in its opposite position and locked out to be deenergized whenever the track switch is unlocked or is being operated to a new position, a neutral-polar indication relay having its windings included in series in said indication circuit, said relay having a neutral armature and a polar armature for respectively operating neutral and polar contacts, normal and reverse neutral repeater relays, two rectifier units, an energizing circuit for said normal repeater relay including the polar contact of said indication relay in one position and a contact closed when said control means is in a corresponding normal position with one of said rectifier units connected in series with said circuit and directly across the windings of said indication relay, and an energizing circuit for said reverse repeater relay including 1e polar contact of said indication relay in its opposite position and a contact closed when said control means is in a corresponding reverse position with the other rectifier unit connected in series with said circuit and directly across the windings of said indication relay, whereby the energization of a normal or reverse repeater relay is effected only when the track switch is in a normal or reverse position and locked and only providing a governing control for the track switch to the-same position is given by said control means, and whereby the failure of the polar armature or said indication relay to respond to the energization of said indication circuit does not result in the false energization of said repeater relays.

6. In an indication and control circuit organization for a railroad track switch, control relay means associated with the track switch and including contacts for governing the normal and reverse operation of the track switch as required, point detector contacts associated with the track switch and caused-to assume normal or reverse positions in correspondence with the then existing position of the track switch provided it is locked, but caused to assume a different position when the track switch is being operated or is unlocked, a neutral-polar indication relay having both neutral and polar armatures for respectively operating neutral and polar contacts, a polarized indication circuit including a source of energy, said point detector contacts and the windings of said indication relay to thereby cause said relay to pick up its neutral armature whenever it is energized but to operate its polar armature to opposite positions in accordance with the polarity of energy then applied to said indication circuit, two rectifier units, circuit means for connecting said rectifier units in series and oppositely poled across the windings of said indication relay, normal and reverse neutral repeater relays, and energizing circuits connecting one terminal of each repeater relay to opposite sides of the windings of said indication relay, and said circuits also including neutral and polar contacts of said indication relay to connect a midpoint between said two rectifiers to one repeater relay or the other depending upon the position of the polar contact and including a corresponding normal or reverse contact of said control relay means, whereby said normal and reverse repeater relays are energized when said track switch is in corresponding normal or reverse positions only providing said control relay means is in the same position, and whereby said rectifier units serve to provide a check upon the response of the polar contacts of said indication relay.

'7. A circuit organization for governing signal circuits in accordance with the position of power operated switch points comprising in combination, a control circuit energized with a normal polarity or a reverse polarity when said switch points are in a corresponding normal or reverse position, a neutral-polar indication relay having its winding included in said control circuit and having neutral and polar contacts, normal and reverse neutral repeater relays having energizing circuits for their respective windings connected to said control circuit and governed by the neutral and polar contacts of said indication relay, and a rectifier connected in series with the neutral repeater relay winding in each of said energizing circuits and polarized so as to block the fiow of current through the corresponding repeater relay when the polarity of said control circuit is the reverse of that normally employed for energizing that relay, and said series connection of the rectifier being such as to prevent the fiow of energy of either polarity to the winding of the associated neutral relay in case the rectifier should become open circuited.

ROBERT F. WELLS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,778,543 Vlood Oct. 14, 1930 2,096,934 Hitchcock Oct. 26, 193'! 2,351,495 Dodd June 13, 1944 2,365,641 Jerome Dec. 19, 1944 2,378,751 Crago June 19, 1945 

